Basis of Structural Design (En1990 2002)Loadings Snow Wind

7/28/2019 Basis of Structural Design (En1990 2002)Loadings Snow Wind

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BASIS OF STRUCTURAL DESIGN

(EN1990:2002)

Ultimate limit state verification

(EN1990,cl.6.4.1(1)P)

The following ultimate limit states shall be verified as relevant:

EQU: Loss of equilibrium of the structure, (considering for sliding, overturning or uplift)

STR: Internal failure or excessive deformation of the structure of structural member (Design of structural for

strength of members and frames),

GEO: Failure due to excessive deformation of the ground (Design of structural members such as footing,

piles, basement walls, etc.),

FAT: Fatigue failure of the structure or structural member.

Design working life

(CYS NA EN1990,Table 2.1)

Design working lifecategory

Indicative designworking life (years)

Examples

1 10 Temporary structures(1)

2 1025 Replaceable structural parts, e.g. gantry girders,

bearings

3 1530 Agricultural and similar structures

4 50 Building structures and other common structures

5 100 Monumental building structures, bridges, and other

civil engineering structures

(1) Structures or parts of structures that can be dismantled with a view to being re-used should

not be considered as temporary.In the case of replaceable structural parts the design life for the structural determination of loads should be

the design life of the structure.

Design Working life

Ultimate Limit State (ULS)

Ultimate Limit State Concern

(EN1990,cl.3.3(1)P)

Safety of people, Safety of the structure

Design situations

(EN1990,cl.3.2(2)P)

Persistent design situation: Normal use condition

Transient design situation: Temporary condition, e.g. during execution or repair

Accidental design situation: Exceptional condition, e.g. fire, explosion, impact.

Seismic design situation: Structure subject to seismic events.


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Ultimate Limit State (ULS)

COMBINATION OF ACTIONS FOR PERSISTENT/TRANSIENT DESIGN SITUATION

(EN1990,cl.6.4.3.2)

Persistent and transient design situationEQU Equation 6.10 (Set A)

6.10 Ed=G Gk+Q Qk1 + Q 0,2 Qk2

ActionFavourable

Unfavourable

Permanent (dead,

earth), G0.9 1.1

Variable (imposed,

wind), Q0 1.5

Note: Single source is not applicable for EQU design situation. Different factors can be used in favourable and unfavourable

areas.

Persistent and transient design situationSTR/GEO Equation 6.10, 6.10a & 6.10b (Set B)

6.10

6.10a

6.10b

Ed=G Gk+Q Qk1 + Q 0,2 Qk2

Ed=G Gk+Q0,1 Qk1 + Q 0,2 Qk2

Ed=G Gk+Q Qk1 + Q 0,2 Qk2

ActionFavourable

Unfavourable

Permanent (dead,

earth), G1.0 1.35

Variable (imposed,wind), Q

0 1.5

Note: Single source is applicable for STR/GEO design situation.

Persistent and transient design situationGEO Equation 6.10 (Set C)

6.10 Ed=G Gk+Q Qk1 + Q 0,2 Qk2

ActionFavourable

Unfavourable

Permanent (dead,

earth), G1.0 1.0

Variable (imposed,

wind), Q0 1.3

Note: Single source is applicable for STR/GEO design situation.

Important notes

(EN1990,cl.3.2(2)P)

Approach 2 (CYS NA EN1990,Table.A1.2(B)) should be used for thedesign of the structural members of substructure (i.e. footings, piles,

basement walls, etc.) (CYS NA EN1990,cl. 2.2.3.4).

Actions that cannot exist simultaneously due to physical of functionalreasons should not be considered together in combination.

The use of expression 6.10a and 6.10b lead to a more economicdesign in most circumstances.


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Summary table of partial, combination and reduction factors for the STR and GEO ultimate limit states forbuildings

Expression

Unfavourable Permanent action Unfavourable Variable actions

Self-weight Imposed floor loads Wind loads Snow loads

6.10

G=1.35 Q,1 =1.5 Q,i0,i =1.5x05=0.75 Q,i0,i =1.5x05=0.75

G=1.35 Q,i0,i =1.5x07=1.05 Q,1 =1.5 Q,i0,i =1.5x05=0.75

G=1.35 Q,i0,i =1.5x07=1.05 Q,i0,i =1.5x05=0.75 Q,i =1.5

Less favourable equations 6.10a & 6.10b

6.10a

G=1.35 Q,i0,i =1.5x07=1.05 Q,i0,i =1.5x05=0.75 Q,i0,i =1.5x05=0.75

G=1.35 Q,i0,i =1.5x07=1.05 Q,i0,i =1.5x05=0.75 Q,i0,i =1.5x05=0.75

G=1.35 Q,i0,i =1.5x07=1.05 Q,i0,i =1.5x05=0.75 Q,i0,i =1.5x05=0.75

6.10b

G=0.85*1.35 Q,1 =1.5 Q,i0,i =1.5x05=0.75 Q,i0,i =1.5x05=0.75

G=0.85*1.35 Q,i0,i =1.5x07=1.05 Q,1 =1.5 Q,i0,i =1.5x05=0.75

G=0.85*1.35 Q,i0,i =1.5x07=1.05 Q,i0,i =1.5x05=0.75 Q,i =1.5

Note: Shaded boxes indicate the leading variable action,

Combination (sensitivity) factor,

(CYS NA EN1990:2002, Table A1.1)

Category Specific Use 1 2

A Domestic and residential 0.7 0.5 0.3

B Office 0.7 0.5 0.3

C Areas for Congregation 0.7 0.7 0.6

D Shopping 0.7 0.7 0.6E Storage 1.0 0.9 0.8

F Traffic < 30 kN vehicle 0.7 0.7 0.6

G Traffic < 160 kN vehicle 0.7 0.5 0.3

H Roofs 0.7 0 0

Snow, altitude < 1000 m 0.5 0.2 0

Wind 0.5 0.2 0


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Serviceability Limit State (SLS)

COMBINATION OF ACTIONS FOR SERVICEABILITY LIMIT STATE

(EN1990,cl.6.5.3)

Characteristic combination

Equation 6.14bEd=Gk+Qk,1 + 0 Qk,2

Frequent combination

Equation 6.15bE

d=G

k+

1Q

k,1+

2Q

k,2

Quasi-permanent combination

Equation 6.16bEd=Gk+ 2Qk,1

Characteristic value of variable actions

For each variable action there are four representative values:

1.The characteristic value Qk(determine by insufficient data).

2.The combination value 0Qk(of an action is intended to take account of the

reduced probability of the simultaneous of two or more variable actions).

3. Frequent value 1Qk (exceeded only for a short period of time and is used

primary for the SLS and also the accidental ULS).

4. Quasi-permanent value 2Qk(exceeded for a considerable period of time or

considered as an average loading over time and used for the long-term affects

at the SLS and also accidental and seismic ULS).

INDICATIVE LIMITING VALUES FOR VERTICAL DEFLECTIONS

(Manual of EC0 &EC1, Table D.1)

Serviceability Limit States

Vertical deflections

Serviceability Requirement Characteristic Combination (Expression 6.14bin EC0) wmax

Function and damage to non-

structural elements (e.g.

partition walls claddings etc)

Brittle

-Non-brittleFunction and damage to

structural elements

L/500 to L/360

L/300 to L/200

L/300 to L/200

Serviceability Limit State (SLS)Vertical and Horizontal deformations


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INDICATIVE LIMITING VALUES FOR HORIZONTAL DEFLECTIONS

(Manual of EC0 &EC1, Table D.2)

Serviceability Limit States

Vertical deflections

Serviceability Requirement Characteristic Combination (Expression 6.14bin EC0) wmax

Function and damage to non-

structural elements

Single storey buildings top

of column

-Each storey in a multi-storey

building

-The structure as a whole for

a multi-storey building

uH/300

uH/500 to H/300

uH/500


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Category of use

(EN1991-1-1:2002,Table 6.1)

Category Specific Use Example

A Area for domestic and

residential activities

Rooms in residential buildings and houses bedrooms and wards in

hospitals, bedrooms in hotels and hostels kitchens and toilets

B Office areas

C Areas where people may

congregate (with the

exception of areas

defined under category

A, B, and D1))

C1: Areas with tables, etc. e.g. areas in schools, cafs, restaurants,

dining

halls, reading rooms, receptions.

C2: Areas with fixed seats, e.g. areas in churches, theatres or

cinemas, conference rooms, lecture halls, assembly halls, waiting

rooms, railway waiting rooms.

C3: Areas without obstacles for moving

people, e.g. areas in museums, exhibition rooms, etc. and access

areas in public and administration buildings, hotels, hospitals,railway station forecourts.

C4: Areas with possible physical activities, e.g. dance halls,

gymnastic rooms, stages.C5: Areas susceptible to large crowds, e.g. in buildings for public

events like concert halls, sports halls including stands, terraces and

access areas and railway platforms.

D Shopping areas D1: Areas in general retail shops

D2:Areas in departments stores

Imposed loads

(EN 1991-1-1:2002, Table 6.2)

Category Of loaded areas qk

(kN/m2)

Qk

(kN)

Category A

-Floors

-Stairs

-Balconies

Category B

Category C

-C1

-C2

-C3

-C4

-C5

Category D

-D1

-D2

1.5-2.0

2.0-4.0

2.5-4.0

2.0-3.0

2.0-3.0

3.0-4.03.0-5.0

4.5-5.0

5.0-7.5

4.0-5.0

4.0-5.0

2.0-3.0

2.0-4.0

2.0-3.0

1.5-4.5

3.0-4.0

2.5-7.04.0-7.0

3.5-7.0

3.5-4.5

3.5-7.0

3.5-7.0Imposed load on Roof

(CYS NA EN1991-1-1, Table 6.10)

Sub-category Actions

Imposed load,

qk

(kN/m2) Q (kN)

HRoof (inaccessible except for

normal maintenance and repair) 0.4 1.0

STRUCTURAL LOADS

(EN1991:2002)

Imposed Loads


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Permanent load

(EN 1991-1-1:2002, Table A.1-A.12)

Materials Density,

(kN/m3)

Modulus of

Elasticity, E

kN/mm2

Reinforced Concrete

Steel

Glass

Water

Plastic PTFE

Softwood timber

Hardwood timber

Concrete blockwork

Asphalt

Roof tiles

Soil (Sand)

Soil (Clay)

Insulation boardAluminium

Copper

Cement mortar

ylon

Epoxy resin

Polystyrene

Carbon fibre

Fibre glass

Granite

25

78

25

10

21-22

57

18

22

20

16-18

20-22

327

87-89

19-23

11.516-20

10-13

20

15

26

17-31

210

74

-

0.3-0.6

1012

-

-

5-30

-

-

-69

96

20-31

2-3.520

3-3.3

415

10

40-70

Permanent Loads

Typical unit floor Typical loadings Typical unit floor Typical loadings

Steel floor kN/m2

Self weight of beam 0.25

Self weight of decking 0.10

Self weight of meshing 0.05

Ceiling and services 0.15

Total 0.55

Internal ConcreteFloor kN/m2

Partition (minimum) 1.00

Screed (5-70cm) 1.20-1.80

Raised floor 0.40

Concrete floor (15cm) 3.75

Celling and services 0.15

Total 6.50-7.10

External Concrete Floor kN/m

2

Slabs / paving 0.95

Screed (50cm) 1.20

Asphalt waterproofing 0.45

Concrete floor (15cm) 3.75


Total 6.50

Metal deck roofing kN/m

2

Live loading: snow/

wind uplift 0.6-1.0

Outer covering, insulation and

metal deck liner 0.30

Purlins-150 deep at 1.5m c/c 0.10

Services 0.10

Total 1.1-1.5

Timber Floor kN/m2

Partition 1.00

Timber boards/plywood 0.15

Timber joist 0.20


Total 1.50

Timber Flat Roof kN/m2

Asphalt waterproofing 0.45

Timber joist and insulation 0.20


Total 0.80


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SNOW LOAD(EN1991-1-3)

Snow load on roof for transient design situations

s=iCeCtsk

(EN 1991-1-3Equ.5.1)

Snow load shape coefficients,

(EN1991-1-3, Table 5.2)

Angle of pitch of

roof, a

030 30

60

60

1 0.8 0.8(60-)/30 0

2 0.8+0.8 /30 1.6 -

For monopitch roof use only 1

For pitched roof use 1and2

THERMAL COEFFICIENTS C

(1991-1-32003, cl. 5.2(8))

Ct=1.0

Thermal transmission on the roof

60

60

3 should be less than32 0 0.2+10 h/b

Monopitch roof Pitch roof Cylinder roof


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WIND LOAD(EN1991-1-4)

Fundamental Basic wind velocity, vb,0

(CYS NA EN1991-1-4,Fig.1)

Directional factor

(CYSEN1991-1-4,NA 2.4)

cdir=1.0(Conservative value for all direction)

Season factor

(CYS EN1991-1-4,NA 2.4)

cseason=1.0

Basic wind velocity

(EN1991-1-4, Eq. 4.1)

vb=cdir.cseasonvb,0

BASIC WIND VELOCITY


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STRUCTURAL FACTOR(EN1991-1-4, cl.6.0)

cscd =1.0

Builiding with less than

h15m

Natural frequency

f5Hz

Walls100m high Chimney with circular

cross-sectional area and,

h60m

h6.5diameter

Determination of cscd

Determine of structural factor cscd

Size factor

(EN1991-1-4,Eq.6.2)

It is on the safe side to use

B2=1 kp=3

Calculation of R2

can be found in Annex B of

EN1991-1-4:2005

Dynamic factor

(EN1991-1-4,Eq.6.3)

It is on the safe side to use

B2=1 kp=3

Calculation of R2

can be found in Annex B of

EN1991-1-4:2005

Consider Ignore

Upwind Slope3o

NOYES

TERRAIN OROGRAPHY,

(EN1991-1-4, cl.4.3.3)

Detail calculation of terrain orography

factor can be found in Annex A of

EN1991-1-4:2005


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PEAK VELOCITY PRESSURE

Roughness factor, cr(z)

(EN1991-1-4,Eq.4.3-4.5)

cr(z)=kr . ln(z/z0) for zminzzmax

cr(z)=cr . (zmin) for zzmin

z0: is the roughness length

Maximum height, zmax

(EN1991-1-4, cl. 4.3.2)

zmax=200m

Orography factor co(z)

co(z)=1

Terrain factor,

(EN1991-1-4,cl.4.4)

kr=0.19(z0/z0,II)0.07

Mean wind velocity, vm(z)

(EN1991-1-4 cl.4.3.1 )

vm(z)=cr(z).co(z).vb

Wind turbulence, Iv(z)

(EN1991-1-4,Eq.4.7)

Iv(z)=v/vm(z)=kl/co(z)ln(z/z0) for

zminzzmax

Iv(z)=Iv(zmin) for zzmin

Turbulence factor: kl=1.0

(NA CYS EN1991-1-4, cl. NA 2.10)

Note: for co(z)=1 Iv(z) is not important

Peak velocity pressure, qpeak(z)

(EN1991-1-4 Eq.4.8 )

qpeak(z)=[1+7 Iv(z)]0.5 vm2

Terrain category and terrain parameters (EN1991-1-4, Tab.:4.1)

Terrain

category

Description z0 (m) zmin(m)

0Sea, costal area exposed to the open

sea. SEA 0.003 1

ILakes or area with negligiblevegetation and without obstacles.

COUNTRY

0.01 1

II

Area with low vegetation such as

grass and isolated obstacles trees,

buildings) with separations of at least

20 obstacle height.

0.05 2

III

Area with regular cover of vegetation

or buildings or woth isolatd obstacles

with seperations of maximum 20

obstacle height (such as villages,

suburban terrain, permanent forest).TOWN

0.3 5

IV*

Area in which at least 15% of the

surface is covered with building and

their average height exceeds 15m.

1.0 10

* For buildings in terrain category IV, displacement height hdis should be consider and information can be found in Aneex A.5 of EN1991-1-4:2005


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Values of external pressure coefficient for vertical walls of rectangular plan buildings

(EN1991-1-4, Tab.:4.1)

ZONE A B C D E

h/d cpe,10 cpe,1 cpe,10 cpe,1 cpe,10 cpe,1 cpe,10 cpe,1 cpe,10 cpe,1

5 -1.2 -1.4 -0.8 -1.1 -0.5 +0.8 +1.0 -0.7

1 -1.2 -1.4 -0.8 -1.1 -0.5 +0.8 +1.0 -0.5

0.25 -1.2 -1.4 -0.8 -1.1 -0.5 +0.7 +1.0 -0.3

Note: Values forcpe,1are intended for the design of small elements and fixings with an element of 1m2

or

less such as cladding elements and roofing elements. Values for cpe,10 may be used for the design of the

overall load bearing structure of buildings. The external pressure coeffiecient cpe,1 and cpe,10 is using for

loadaded area of 1m2

and 10m2

respectively.

Reference height ze, depending on hand b, and corresponding velocity pressure profile

(EN1991-1-4, Fig. 7.4)

Key for vertical wallsFlat Roof

(EN1991-1-4, Fig.7.5)

Key for vertical wallsMono&dual pitch

Roof

(EN1991-1-4, Fig.7.5)

Pressure on surface &Wind force (EN1991-1-4, Eq. 5.1&5.5)

we=qp(ze).(cpe +cpi) & Fw=cscdweAref

EXTERNAL WIND PRESSURE/FORCE ON WALLS


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EXTERNAL WIND PRESSURE/FORCE ON FLAT ROOF

Recommended values of external pressure coefficients for flat roofs

(EN1991-1-4,Tab. 7.2)

Roof type

Zone

F G H I

cpe,10 cpe,1 cpe,10 cpe,1 cpe,10 cpe,1 cpe,10 cpe,1

Sharp eaves -1.8 -2.5 -1.2 -2.0 -.07 -1.2 +0.2

With

Parapets

hp/h=0.025 -1.6 -2.2 -1.1 -1.8 -0.7 -1.2 -0.2

hp/h=0.05 -1.4 -2.0 -0.9 -1.6 -0.7 -1.2 +0.2hp/h=0.10 -1.2 -1.8 -0.8 -1.4 -0.7 -1.2 -0.2

Curved

Eaves

r/h=0.05 -1.0 -1.5 -1.2 -1.8 -0.4 +0.2

r/h=0.10 -0.7 -1.2 -0.8 -1.4 -0.3 -0.2

r/h=0.20 -0.5 -0.8 -0.5 -0.8 -0.3 +0.2

Mansard

Eaves

a=30o

-1.0 -1.5 -1.0 -1.5 -0.3 -0.2

a=45o

-1.2 -1.8 -1.3 -1.9 -0.4 +0.2

a=60o

-1.3 -1.9 -1.3 -1.9 -0.5 -0.2


or

less such as cladding elements and roofing elements. Values for cpe,10 may be used for the design of the

overall load bearing structure of buildings. The external pressure coeffiecient cpe,1 and cpe,10 is using for

loadaded area of 1m2

and 10m2

respectively.




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Recommended values of external pressure coefficients for monopitch roofs

(EN1991-1-4,Tab. 7.3a)

Pitch

Angle

a

Zone for wind direction =0o


F G H F G H

cpe,10 cpe,1 cpe,10 cpe,10 cpe,1 cpe,10 cpe,10 cpe,1 cpe,10 cpe,1 cpe,10 cpe,1

5o -1.7 -2.5 -1.2 -2.0 -0.6 -1.2 -2.3

-2.5 -1.3 -2.0 -0.8 -1.2+0.0 +0.0 +0.0

15o -0.9 -2.0 -0.8 -1.5 -0.3

-2.5 -2.8 -1.3 -2.0 -0/9 -1.2+0.2 +0.2 +0.2

30o -0.5 -1.5 -0.5 -1.5 -0.2-1.1 -2.3 -0.8 -1.5 -0.8

+0.7 +0.7 +0.4

45o -0.0 -0.0 -0.0

-0.6 -1.3 -0.5 -0.7+0.7 +0.7 +0.6

60o

+0.7 +0.7 +0.7 -0.5 -1.0 -0.5 -0.5

75o

+0.8 +0.8 +0.8 -0.5 -1.0 -0.5 -0.5

Recommended values of external pressure coefficients for monopitch roofs

(EN1991-1-4,Tab. 7.3b)

Pitch

Anglea


Fup Flow G H Icpe,10 cpe,1 cpe,10 cpe,10 cpe,1 cpe,10 cpe,10 cpe,1 cpe,10 cpe,1

5o

-2.1 -2.6 -2.1 -2.4 -1.8 -2.0 -0.6 -1.2 -0.5

15o

-2.4 -2.9 -1.6 -2.4 -1.9 -2.5 -0.8 -1.2 -0.7 -1.2

30o

-2.1 -2.9 -1.3 -2.0 -1.5 -2.0 -1.0 -1.3 -0.8 -1.2

45o

-1.5 -2.4 -1.3 -2.0 -1.4 -2.0 -1.0 -1.3 -0.9 -1.2

60o

-1.2 -2.0 -1.2 -2.0 -1.2 -2.0 -1.0 -1.3 -0.7 -1.2

75o

-1.2 -2.0 -1.2 -2.0 -1.2 -2.0 -1.0 -1.3 -0.5


or less such

as cladding elements and roofing elements. Values forcpe,10 may be used for the design of the overall load bearing

structure of buildings. The external pressure coeffiecient cpe,1 and cpe,10 is using for loadaded area of 1m2

and 10m2

respectively.

EXTERNAL WIND PRESSURE/FORCE ON MONOPITCH ROOF




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Recommended values of external pressure coefficients for duopitch roofs(EN1991-1-4,Tab. 7.4a)

Pitch

Anglea


F G H I J

cpe,10 cpe,1 cpe,10 cpe,10 cpe,1 cpe,10 cpe,10 cpe,1 cpe,10 cpe,1

-45o

-0.6 -0.6 -0.8 -0.7 -1.0 -1.5

-30o

-1.1 -2.0 -0.8 -1.5 -0.8 -0.6 -0.8 -1.4

-15o

-2.5 -2.8 -1.3 -2.0 -0.8 -1.2 -0.5 -0.7 -1.2

-5o

-2.3 -2.5 -1.2 -2.0 -0.8 -1.2+0.2 +0.2

-0.6 -0.6

5o

-1.7 -2.5 -1.2 -2.0 -0.6 -1.2-0.6

+0.2

+0.0 +0.0 +0.0 -0.6

15o

-0.9 -2.0 -0.8 -1.5 -0.3 -0.4 -1.0 -1.5

+0.2 +0.2 +0.2 +0.0 +0.0 +0.0

30o

-0.5 -1.5 -0.5 -1.5 -0.2 -0.4 -0.5

+0.7 +0.7 +0.4 +0.0 +0.0

45o

-0.0 -0.0 -0.0 -0.2 -0.3

+0.7 +0.7 +0.6 +0.0 +0.0

60o

+0.7 +0.7 +0.7 -0.2 -0.3

75o

+0.8 +0.8 +0.8 -0.2 -0.3

Recommended values of external pressure coefficients for duopitch roofs

(EN1991-1-4,Tab. 7.4b)

Pitch

Angle a


F G H Icpe,10 cpe,1 cpe,10 cpe,10 cpe,1 cpe,10 cpe,10 cpe,1

-45o

-1.4 -2.0 -1.2 -2.0 -1.0 -1.3 -0.9 -1.2

-30o

-1.5 -2.1 -1.2 -2.0 -1.0 -1.3 -0.9 -1.2

-15o

-1.9 -2.5 -1.2 -2.0 -0.8 -1.2 -0.8 -1.2

-5o

-1.8 -2.5 -1.2 -2.0 -0.7 -1.2 -0.6 -1.2

5o

-1.6 -2.2 -1.2 -2.0 -0.7 -1.2 -0.6

15o

-1.3 -2.0 -1.2 -2.0 -0.6 -1.2 -0.5

30o

-1.1 -1.5 -1.4 -2.0 -0.8 -1.2 -0.5

45o

-1.1 -1.5 -1.4 -2.0 -0.9 -1.2 -0.5

60o

-1.1 -1.5 -1.4 -2.0 -0.8 -1.2 -0.5

75o -1.1 -1.5 -1.4 -2.0 -0.8 -1.2 -0.5

EXTERNAL WIND PRESSURE/FORCE ON DUOPITCH ROOF



Basis of Structural Design (En1990 2002)Loadings Snow Wind

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